Thank you for the pointers! After digging into this some more, I found that this is definitely related to something in cartain versions of SQLAlchemy. I also tried different versions of cx_Oracle (6.4.1, 7.1.2, and 7.1.3) but that had no effect on the performance of the statement.
I did not try all possible combinations of SQLAlchemy and cx_Oracle but I tried to do a little bisection on the SQLAlchemy version while keeping cx_Oracle fixed at 7.1.3. What I found: - 1.3.0 and above: Fine! - 1.2.19*: *slow - 1.2.12: slow - 1.2.6: slow - 1.2.3: slow - 1.2.2: slow - 1.2.1: Fine - 1.2.0: Fine - 1.1,18: Fine So, the culprint is SQLAlchemy 1.2.2 and 1.3.0 fixes whatever was wrong. While that solves my problem in an elegant way (I wanted to upgrade to 1.3+ anyway) I will still try to find the root cause by profiling my application the way you suggested. Maybe something can be learned from that to avoid future regressions. However, that will take some time. I will be back with the results, later! -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at https://groups.google.com/group/sqlalchemy. To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/1a2c2fdb-9de4-4679-b7a0-940974f6e507%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
